Soliton molecules: 4 Symbols for quaternary data transmission

In dispersion managed fibers, solitons can form bound states: so-called soliton molecules. Soliton molecules consisting of two pulses have been experimentally verified some time ago[1], and their binding mechanism was explained in [2]. Here we present the first experimental verification of a soliton molecule consisting of three pulses. This is a significant result because the set of no pulse, single soliton, 2-soliton molecule and 3-soliton molecule has four symbols which can be used for quaternary data transmission in a soliton format.